1. Field of the Invention
The present invention relates to inflatable flotation devices. In particular, the present invention relates to inflatable flotation devices which are collapsible through use of a spring mechanism.
2. Description of the Related Art
Inflatable flotation devices are well known in the form of floats, rafts, lifeboats, life preservers and other like devices. Previously known devices generally maintain their shape through air pressure alone and generally collapse when deflated.
In one of many examples, U.S. Pat. No. 3,775,782 issued to Rice et al. describes an inflatable rescue raft. When deflated, the raft can be rolled into a compact size.
Also well known in the art are collapsible items which are collapsible through the use of a collapsible metal or plastic spring. U.S. Pat. No. 4,815,784 shows an automobile sun shade which uses these collapsible springs. The springs are also used in children's play structures (U.S. Pat. Nos. 5,618,246 and 5,560,385) and tent-like shade structures (U.S. Pat. Nos. 5,579,799 and 5,467,794).
The collapsible springs are typically retained or held within fabric sleeves provided along the edges of a piece of fabric or other panel. The collapsible springs may be provided as one continuous loop, or may be a strip or strips of material connected at the ends to form a continuous loop. These collapsible springs are usually formed of flexible coilable steel, although other materials such as plastics are also used. The collapsible springs are usually made of a material which is relatively strong and yet is flexible to a sufficient degree to allow it to be coiled. Thus, each collapsible spring is capable of assuming two configurations, a normal uncoiled or expanded configuration, and a coiled or collapsed configuration in which the spring is collapsed into a size which is much smaller than its open configuration. The springs may be retained within the respective fabric sleeves without being connected thereto. Alternatively, the sleeves may be mechanically fastened, stitched, fused, or glued to the springs to retain them in position.